//https://www.bookstack.cn/read/dart-2.7-zh/1b9943e0f451b845.md

void main(){
  //类型转换
 assert(int.parse('23')==23);
 assert(num.parse('42') is int);
 assert(43.toString()=='43');
 //字符
  var a='hell world';
  print(a.contains('other'));
  print(a.split(' '));
  print(a.startsWith('h'));
  print(a.endsWith('w'));
  print(a.indexOf('w'));

  var b='err';
  print(b.trim());
  print(b.isEmpty);

   var c=StringBuffer();
   c..write('w')
    ..write('object')
    ..write('tyy');
   print(c);


}

/**
 * 1.类型转换
 * 2.正则
 *
 *
 */